Closer with hold-open pivot arm



Nov. 10, 1964 R. w, sci-mun 3,156,001

CLOSER WITH HOLD-OPEN PIVOT ARM Filed July 2, 1962 3 Sheets-Sheet 1 7 INVENTOR. M Sum/0 Nov. 10, 1964 R. w. SCHMID 3, 55,001

CLOSER WITH HOLD-OPEN PIVOT ARM Filed July 2, 1962 3 Sheets-Sheet 2w INVENTOR.

@ M SCI/MID Nov. 10, 1964 R. w. SCHMlD CLOSER WITH HOLD-OPEN PIVOT ARM 3 Sheets-Sheet 5 Filed July 2, 1962 53 mw 00 LI United States Patent 3,156,001 CLQSER WITH HOLD-OPEN PHVUT ARM Raymond W. Schmid, ll-Iavertowu, Pa, assignor, by mesne assignments, to Yale & Towne, fine, New York, N.Y., a company of @hio Filed July 2, 1962, Ser. No. 206,619 11 Claims. (Cl. 1664) This invention relates to a hold open mechanism for a door closer.

Door closers are quite frequently provided with hold open mechanisms which will releasably hold the door in an open position. These hold open mechanisms commonly include a detent which is adapted to engage in a notch in a moving part of the closer when the door has been opened to a particular position. The door may be again closed by applying sufficient force to the door to cam the detent out of the retaining notch.

While various detent arrangements have been proposed and used for this purpose, these arrangements have required the use of detent springs of sufficient strength to hold the detents in the retaining notches with such force that the heavy closer spring for returning the door to closed position will not cam the detent from the retaining notch and release the door. Thus, the force exerted by the detent spring on the detent must be correlated to that exerted by the closer spring, and relatively heavy, expensive detent springs must be used with these arrangements. Furthermore, these detent springs occupy considerable space within the closer, thereby increasing the overall sizes of the closer.

The purpose of this invention is to provide a hold open mechanism which utilizes a retaining dog, or detent to hold the door in open position, but which requires no separate spring to move and hold the dog in door holding position. The necessity of the separate expensive springs heretofore used for this purpose, therefore, is eliminated, allowing the closer to have a smaller overall size. This latter advantage makes the hold open arrangement particularly suitable for concealed type closers which must have relatively overall dimensions to allow them to be mounted within the narrow door frame above the door opening.

In accordance with the invention, the hold open mechanism includes a lost motion connection between a pair of movable parts of the closer, and a dog member movable by relative movement between the pair of movable parts. During a major portion of the movement of the movable parts in the door opening direction, the dog member engages a limiting surface and prevents relative movement between the parts. When the movable parts reach a position corresponding to the door open position, the dog is released and the parts are moved relatively to one another by'the compressed closer spring, causing movement of the dog to a position locking the movable parts to the closer body to prevent closing of the door by the compressed closer spring. The door may be again closed by applying force to the door in the closing direction to move one movable part relatively to the other movable part to retract the dog member and allow the closer spring to close the door. I

In the form of the invention as hereafter illustrated and described, the lost motion connection is in the form of a member pivotally attached at spaced points to the pair of movable parts whereby the parts may move relatively to one another through rotation of the member relatively to the parts. The dog member is formed as a portion of the connecting member and is moved to a door holding position through rotation of theconnecting member.

I The invention and its advantages having been broadly described, a more detailed description of one embodiment "ice of the invention is given hereafter by reference to the following drawings, wherein:

FIG. 1 is a perspective view of a door frame and door showing a closer incorporating a hold open mechanism constructed in accordance with the invention concealed within the door frame above the door opening;

FIG. 2 is a sectional view taken on the line 22 of FIG. 1 showing the internal construction of the closer;

FIG. 3 is a top plan view of the closer with the top cover plate removed and parts of the body portion of the closer broken away to reveal the internal construction;

FIG. 4 is a partial top plan view with parts broken away to illustrate the position of the hold open mechanism in holding the door open;

FIG. 5 is a sectional view on the line 55 of FIG. 3;

FIG. 6 is a. sectional View taken on the line 6-6 of FIG. 3;

FIG. 7 is a perspective view of the hold open mechanism as the door is moved toward an open position;

FIG. 8 is a perspective view similar to that of FIG. 7, but showing the movement of the dog member to the door holding position when the door has reached the open position; and

FIG. 9 is a perspective view similar to that of FIG. 8 showing the releasing of the dog member by application of force to the door in the door closing direction.

Referring to the drawings and in particular to FIG. 1, a closer 10 incorporating the hold open mechanism of the invention is shown concealed within the door frame F above the door opening and connected to the door D through an operating shaft 11. As best shown in FIG. 2, the lower end of the operating shaft 11 is provided with flat portions 12 through which the operating shaft 11 is keyed to a plate 13 which in turn is secured to the top of the door D by screws 14.

The closer 11B is of the rack and pinion type, and ineludes, as best shown in FIG. 3, a rack member 15 having opposed sets of rack teeth 16 and 17, and a pinion segment 18 which is secured to the operating shaft 11 and is adapted to mesh with the one set or the other of the rack teeth 16 and 17. When the operating shaft 11 is rotated through opening of the door D in either direction, the pinion segment 18 engages either rack teeth 16 or rack teeth 17 and moves the rack member 15 to the left.

A pair of piston rods 19 and 20 are connected to the rack member 15 by connecting members 21 and 22. As will be described in detail hereafter, the members 21 and 22 form a lost motion connection between the rack member 15 and the piston rods 19 and 20 allowing slight relative movement between the piston rods 19 and 2G and the rack member 15.

As the rack member 15 is moved to the left by opening of the door D, pistons 23 and 24 secured to the ends of the rods 159 and 21} are also moved to the left in fluid filled cylindrical chambers 25 and 26. As the pistons 23 and 24- are moved to the left, coil springs 2'7 and 28, which surround guides 25 and 3% carried by therods 19 and 20, are compressed between the ends 31 and 32 of the cylindrical chambers 25 and 26 and collars 33-and 34,

secured to the rods 19 and 2t) adjacent the pistons 23 and 24. When the door is released, the compressed springs 27 and 28 move the rods 19 and 2t) and rack member 15 to the right causing the door D to close.

As the pistons 23 and 24 are moved to the left incidental V ber 40.

between the cylindrical chambers and 26 on the righthand side of the pistons 23 and 24. Thus the fluid provides little resistance to the opening of the door during a major portion of the movement of the door to door opening position. When, however, the door approaches the open position, the port is covered by the pistons and the fluid must therefore flow from the left-hand side of the pistons to the right-hand side through a port 38 which extends through the wall between the cylindrical chambers 25 and 26 and through a restricted port 39 in a valve mem- This slows down the final movement of the door in a door opening direction to provide what is commonly called back checking. The effective size of the port 39 may be adjusted by rotating the valve member 40.

When the pistons 23 and 24 are moved to the right by the compressed springs 27 and 28 during closing of the door D, a ball check 41, shown in FIG. 5, closes the passage 36 preventing flow of fluid through the port 37, passage 36 and ports 35 and 38 from the right-hand side of the pistons 23 and 24 to the left-hand side of the pistons. The fluid, therefore, must flow through ports 42, 43 and 44, extending through the walls of the cylindrical chambers 25 and 26, through a longitudinally extending passage 45, through restricted ports 46 and 47 in adjustable valve members 43 and 49 which extend into the passage 45, and through a port 50 extending through the walls of the cylindrical chambers 25 and 26 on the left-hand side of the pistons 23 and 24. The regulating valves 43 and 49 may be rotated to vary the effective sizes of the ports 46 and 47 to adjust the rate of flow of fluid from the righthand side of the pistons 23 and 24 to the left-hand side of the pistons to control the movement of the pistons by the springs to prevent slamming of the door.

As the pistons 23 and 24 move to the right, the pistons first cover ports 44 to slow down the movement of the pistons just prior to final closing movement of the door. During the final closing movement, annular grooves 51 and 52, shown in FIG. 3, in the peripheries of the pistons 23 and 24 align with the ports 44 to allow the flow of fluid from the right-hand side of the pistons through the ports 42, 43, 46 44, grooves 51 and 52, and through ports 53 and 54, shown in FIG. 3, extending through the pistons 23 and 24 and communicating with the grooves 51 and 52. The fluid, therefore, bypasses the regulating valve 49 to allow a sudden spurt of movement of the pistons 23 and 24 by the spring 27 and 28 to insure proper latching of the door.

The particular closer 10 illustrated includes two hold open mechanisms constructed in accordance with the invention, one generally indicated at 55 which cooperates with the piston rod 19, and one generally indicated at 56 which cooperates with the piston rod 20. As both these hold open mechanisms are of the same structure and operate in the same manner, only the mechanism 55 will be described in detail.

As best shown in FIGS. 3 and 4, the hold open mechanism 55 includes the connecting member 21 which forms the lost motion connection between the rod 19 and the rack member 15. The connecting member 21 is pivotally connected at 57 to the rack member 15, and is pivotally connected at 58, at a point spaced from the pivot 57, to the end of an extension member 60 of the rod 19. The opposite end of the extension member 60 in turn is connected at 61 to the left-hand end of rod 19.

The connecting member 21 is provided with a dog or detent member 62, forming an integral extension of the connecting member 21 and extending at approximately 90 to a line joining the pivots 57 and 58. As best shown in FIGS. 6, 7, 8 and 9, the extension member 60 is of channel cross section, and the dog or detent member 62 normally extends within the channel of the extension member 60 during the major portion of movement of the extension member 66 with the piston rod 19 and rack member 15 to the left in the door opening direction. The dog or detent member is held in this position by engagement thereof with a limiting surface formed by the outer periphery of a roller 63, as best shown in FIGS. 3 and 7. Roller 63 is rotatably secured at 64 to the body portion 65 of the closer and is free to rotate to decrease friction between it and the dog or detent portion 62. Engagement of the dog or detent member 62 with the roller 63 prevents rotation of the connecting member 21 relatively to the extension member 60, rod 19, and rack member 15, thereby preventing relative movement between the piston rod 19 and the rack member 15.

As best shown in FIGS. 3 and 4, the body portion 65 of the closer is relieved at 66, just to the left of the roller 63, as viewed in FIG. 3, and when the piston rod 19, the rack member 15 and extension member 60 have been moved to a position corresponding to the open position of the door, as shown in FIG. 4, the dog or detent member 62 is released, allowing the connecting member 21 to be rotated in a clockwise direction through relative movement between the piston rod 19 and the rack member 15 affected by the compressed closer spring 27. The outer end of the dog or detent member 62 is thereby moved in the direction of the arrow A behind the roller 63, as shown in FIG. 4, thereby locking the piston rod 19 and rack member 15 against movement in the door closing direction by the compressed closer spring 27. The door D is thereby held in the open position.

This action is best illustrated in FIG. 8, in which the force vector B represents the force exerted on the pivot 57 by the rack member 15 through manual opening of the door, while the force vector C represents the resisting force exerted on the pivot 58 by the compressed closer spring 27 through the rod 19 and the extension 60. The forces B and C thereby exert a force couple on the connecting member 21 causing rotation of the connecting member 21 to move the dog or detent member 62 in the direction of the arrow A. The force C maintains the end of the dog or detent member 62 behind the roller 63, with the roller acting as limiting means through which the dog or detent member 62 locks the piston rod 19 and rack member against movement in the door closing direction by the closer spring 27.

The dog or detent member 62 may be released from the door holding position, as shown in FIG. 4, by applying an external force to the door in the closing direction. This results in a force being applied to the connecting member 21 through the pivot connection 57 in the direction of the arrow E in FIG. 9 causing the connecting member 21 to rotate about the pivot 58 to move the dog or detent member 62 in the direction of the arrow G, releasing the end thereof from the door holding position behind the roller 63, and thereby releasing the rack member and rod 19 for movement by the compressed closer spring 27 to again close the door.

It will be appreciated that the hold open mechanism 56 associated with the piston rod 20 functions in the same manner and at the same time as the hold open mechanism 55, previously described.

As best shown in FIG. 3, the body portion 65 of the closer 10 is formed in two parts, 65a and 65b, with the part 65a providing the cylindrical chambers 25 and 26 for the pistons 23 and 24, and the part 65!) supporting the rack member 15, operating shaft 11 and pinion segment 18. The two parts 65:: and 6511 are secured together by bolts 67 adjacent the extension members 60 so that extension members 60 may be easily assembled in the closer when the two parts 65a and 65b are disassembled.

The outer ends of the cylindrical chambers 25 and 26 are closed by suitable plugs 63 and 69 which may be removed to allow assembly of the pistons 23 and 24, the rods 19 and 30, and the springs 27 and 28 within the chambers 25 and 26.

As best shown in FIG. 2, the operating shaft 11 is mounted for rotation in the part 65b by a lower bearing '70 which is mounted in an annular seat 71 formed in the inner bottom surface of the part 65b, and anupper bearing 72 mounted in a seat 73 formed in the inner surface of a cover 74 which is removably secured to the part 65b by screws 75. The cover 74 may be removed to allow assembly of the shaft 11, bearings 71 and 72, and rack member 15, and to allow attachment of the piston rods 19 and 20 to the rack member 15 through the connecting members 21 and 22.

From the preceding description, it can be seen that there is provided a novel hold open arrangement for a door closer which is very simple, occupies very little space, and requires no spring member for the detent. While the invention has been described in conjunction with a closer incorporating two closer springs and two damping pistons, it will be appreciated that the invention is also applicable to closers incorporating only one closer spring and one damping piston.

It will also be appreciated that while one form of the invention has been shown and described, changes and modifications may be made therein without departing from the spirit and scope of the invention.

I now claim:

1. A hold open mechanism for a door closer of the type having a body portion, a closer spring, and a pair of parts movable relatively to the body portion through which the closer spring is energized as the door is opened and through which the energized closer spring acts to close the door when the door is released, comprising,

a lost motion connection between said pair of movable parts for allowing relative movement between said parts,

a dog member operatively connected to said pair of movable parts and movable by relative movement between said parts,

a limiting surface on said body portion engageable by said dog member during a major portion of the movement of said pair of movable parts in the door opening direction to prevent movement of said dog member and relative movement between said parts,

a relieved portion in said body portion adjacent said limiting surface for releasing said dog member when said pair of movable parts has moved to a position corresponding to the open position of the door to allow relative movement between said pair of movable parts and resulting movement of said dog member to a door holding position, and

limit means on said body portion engaged by said dog member when said dog member is moved to said door holding position whereby to prevent movement of said pair of movable parts in a door closing direction by said closer spring, said dog member being movable to the door releasing position through relative movement between said parts afiected by the application of force to the door.

2. A hold open mechanism for a door closer of the type having a body portion, a closer spring, and a pair of parts movable relatively to the body portion through which the closer spring is energized as the door is opened and through which the energized closer spring acts to close the door when the door is released, comprising a lost motion connection between said pair of movable parts for allowing relative movement between said parts,

a dog member operatively connected to said pair of movable parts and movable by relative movement between said parts,

a roller rotatably mounted on said body portion and providing a limited surface engageable by said dog member during a major portion of the movement of said pair of movable parts in the door opening direction to prevent movement of said dog member and relative movement between said parts,

a relieved portion in said body portion adjacent said roller for releasing said dog member when said pair of movable parts has moved to a position corresponding to the open position of the door to allow relative movement between said pair of movable parts and resulting movement of said dog member to a door holding position behind said roller whereby to prevent movement of said pair of movable parts in a door closing direction by said closer spring, said dog member being movable to the door releasing position through relative movement between said parts affected by the application of force to the door.

3. A hold open mechanism for a door closer of the type having a body portion, a closer spring, and a pair of parts movable relatively to the body portion through which the closer spring is energized as the door is opened and through which the energized closer spring acts to close the door when the door is released, comprising a lost motion connection between said pair of movable parts including a link member pivotally attached at spaced points to said pair of movable parts for allowing relative movement between said pair of movable parts by rotation of said link member relatively to said pair of parts,

a dog member movable to a door holding position through rotation of said link member by relative movement between said pair of movable parts,

a limiting surface on said body portion engageable by said dog member during a major portion of the movement of said pair of parts in the door opening direction to prevent rotation of said link member and relative movement between said pair of parts,

a relieved portion in said body portion adjacent said limiting surface for releasing said dog member when said pair of movable parts has moved to a position corresponding to the open position of the door to allow relative movement between said pair of movable parts and resulting movement of said link member to move said dog member to door holding position, and

limit means on said body portion engaged by said dog portion when said dog portion is moved to said door holding position whereby to prevent movement of said pair of movable parts in a door closing direction by said closer spring, said link member being rotatable to release said dog portion from said limit means through relative movement between said pair of movable parts affected by the application of an external force to the door.

4. A hold open mechanism for a door closer of the type having a body portion, a closer spring, and a pair of parts movable relatively to the body portion through which the closer spring is energized as the door is opened and through which the energized closer spring acts to close the door when the door is released, comprising,

a lost motion connection between said pair of movable parts including a link member pivotally attached at spaced points to said pair of movable parts for allowing relative movement between said pair of movable parts by rotation of said link member relatively to said pair of parts,

a dog portion on said link member movable to a door holding position through rotation of said link member by relative movement between said pair of movable parts,

a limiting surface on said body portion engageable by said dog portion during a major portion of the movement of said pair of parts in the door opening direction to prevent rotation of said link member and relative movement between said pair of parts,

a relieved portion in said body portion adjacent said limiting surface for releasing said dog portion when said pair of movable parts has moved to a position corresponding to the open position of the door to allow relative movement between said pair of movable parts and resulting rotation of said link member to move said dog portion to door holding position, and i a limit means on said body portion engageable by said dog portion when said dog portion is moved to said door holding position whereby to prevent movement of said pair of parts in a door closing direction by said closer spring, said link member being rotatabie to release said dog portion from said limit means through relative movement between said pair of movable parts afiected by the application of an external force to the door.

5. A hold open mechanism for a door closer of the type having a body portion, a closer spring, and a pair of parts movable relatively to the body portion through which the closer spring is energized as the door is opened and through which the energized closer spring acts to close the door when the door is released, comprising a lost motion connection between said pair of movable parts including a link member pivotally attached at spaced points to said pair of movable parts for allowing relative movement between said pair of movable parts by rotation of said link member relatively to said pair of parts,

a dog portion on said link member movable to a door holding position through rotation of said link member by relative movement between said pair of movable parts,

a roller rotatably mounted on said body portion and providing a limiting surface engageable by said dog portion during a major portion of the movement of said pair of parts in the door opening direction to prevent rotation of said link member and relative movement between said pair of parts,

a relieved portion in said body portion adjacent said roller for releasing said dog portion when said pair of movable parts has moved to a position corresponding to the open position of the dor to allow relative movement between said pair of movable parts and resulting rotation of said link member to move said dog portion to door holding position behind said roller, whereby to prevent movement of said pair of movable parts in a door closing direction by said energized closer spring, said dog portion being movable to the door releasing position through relative movement between said pair of parts affected by the application of external force to the door.

6. A hold open mechanism for a door closer of the type having a body portion and a pair of movable parts including a rod and motion transmitting means for transmitting movement of the door to said rod, a compression spring connected at one end to said rod and reacting at the other end against said body portion, whereby said spring is compressed as the door is opened and the compressed spring acts to close the door when the door is released, comprising a lost motion connection between said motion transmitting means and said rod for allowing relative movement between said motion transmitting means and said rod,

a dog member operatively connected with said lost motion connection and movable by relative movement between said pair of parts,

a limiting surface on said body portion engageable by said dog member during a major portion of the movement of said pair of parts in the door opening direction to prevent relative movement between said pair of parts, i

a relieved portion in said body portion adjacent said limiting surface for releasing said dog member when said pair of parts are moved to a position corresponding to the open position of the door whereby the compressed closer spring causes relative movement between said pair of parts With resulting movement of said dog member to a door holding position, and

limit means on said body portion engaged by said dog member when said dog member is moved to said door holding position whereby to prevent movement of 8 said pair of parts in a door closing direction by said compressed closer spring, said dog member being movable to door releasing position through relative movement between said pair of parts affected by the application of external force to the door.

7. A hold open mechanism for a door closer of the type having a body portion and a pair of movable parts including a rod and motion transmitting means for transmitting movement of the door to said rod, a compression spring connected at one end to said rod and reacting at the other end against said body portion whereby said spring is compressed as the door is opened and the compressed spring acts to close the door when the door is released, comprising a lost motion connection between said motion transmitting means and said rod including a link member pivotally attached at spaced points to said motion transmitting means and to said rod for allowing relative movement between said motion transmitting means and said rod through rotation of said link member relatively to said pair of parts,

a dog member operatively connected to said link member and movable by rotation of said link member,

a limiting surface on said body portion engageable by said clog member during a major portion of the movement of said pair of parts in the door opening direction to prevent rotation of said link member and relative movement between said pair of parts,

a relieved portion in said body portion adjacent said limiting surface for releasing said dog member when said pair of parts are moved to a position corresponding to the open position of the door whereby the compressed closer spring causes relative movement between said pair of parts with resulting rotation of said link member and movement of said dog member to a door holding position, and

limit means on said body portion engage by said dog member when said dog member is moved to said door holding position whereby to prevent movement of said pair of parts in a door closing direction by said compressed closer spring, said dog member being movable to door releasing position through relative movement between said pair of parts affected by the application of external force to the door.

8. A hold open mechanism for a door closer 0f the type having a body portion and a pair of movable parts including a rod and motion transmitting means for transmitting movement of the door to said rod, a compression spring connected at one end to said rod and reacting at the other end against said body portion whereby said spring is compressed as the door is opened and the compressed spring acts to close the door when the door is released, comprising a lost motion connection between said motion transmitting means and said rod including a link member pivotally attached at spaced points to said motion transmitting means and to said rod for allowing relative movement between said motion transmitting means and said rod through rotation of said link member relatively to said pair of parts,

a dog member operatively connected to said link member and movable by rotation of said link member,

a roller on said body portion engageable by said dog member during a major portion of the movement of said pair of parts in the door opening direction to prevent rotation of said member and relative movement between said pair of parts,

a relieved portion is said body portion adjacent said roller for releasing said dog member when said pair of parts are moved to a position corresponding to the open position of the door whereby the compressed closer spring causes relative movement between said pair of parts with resulting rotation of said link member and movement of said dog member to a door holding position behind said roller to prevent movement of said pair of parts in a door closing direction by said compressed closer spring, lsaid dog member being movable to the door releasing position through relative movement between said pair of parts affected by the application of external force to the door.

9. hold open mechanism for a door closer of the type having a body portion and a pair of movable parts including a rod and a rack member for transmitting movement of the door to said rod, a compression spring connected at one end to said rod and reacting at the other end against said body portion whereby said spring is compressed as the door is opened and the compressed spring act to close the door when the door is released, comprising a lost motion connection between said rack member and said rod including a link member pivotally attached at spaced points to said rack member and to said rod for allowing relative movement between said rack member and said rod through rotation of said link member relatively to said pair of parts,

a dog member operatively connected to said link member and movable by rotation of said link member,

a limiting surface on said body portion engageable by said dog member during a major portion of the movement of said pair of parts in the door opening direction to prevent rotation of said link member and relative movement between said pair of parts,

a relieved portion in said body portion adjacent said limiting surface for releasing said dog member when said pair of parts are moved to a position corresponding to the open position of the door whereby the compressed closer spring causes relative movement between said pair of parts with resulting rotation of said link member and movement of said dog member to a door holding position, and

limit means on said body portion engaged by said dog member when said dog member is moved to said door holding position whereby to prevent movement of said pair of parts in a door closing direction by said compressed closer spring, said dog member being movable to the door releasing position through relative movement between said pair of parts affected by the application of external force to the door.

10. A hold open mechanism for a door closer of the type having a body portion and a pair of movable parts including a rod and a rack member for transmitting movement of the door to said rod, a compression spring connected at one end to said rod and reacting at the other end against said body portion whereby said spring is compressed as the door is opened and the compressed spring acts to close the door when the door is released, comprising a lost motion connection between said rack member and said rod including a link member pivotally attached at spaced points to said rack member and to said rod for allowing relative movement between said rack member and said rod through rotation of said link member relatively to said pair of parts,

a dog portion on said link member movable by rotation of said link member through relative movement between said pair of parts,

a limiting surface on said body portion engageable by said dog portion during a major portion of the movement of said pair of parts in the door 50 opening direction to prevent rotation of said link member and relative movement between said pair of parts,

a relieved portion in said body portion adjacent said limiting surface for releasing said dog portion when said pair of parts are moved to a position corresponding to the open position of the door whereby the compressed closer spring causes relative movement between said pair of parts with resulting rotation of said link member and movement of said dog portion to a door holding position, and

limit means on said body portion engaged by said dog portion when said dog portion is moved to said door holding position whereby to prevent movement of said pair of parts in a door closing direction by said compressed closer spring, said dog portion being movable to the door releasing position through relative movement between said pair of parts affected by the application of external force to the door. 11. A hold open mechanism for a door closer of the type having a body portion and a pair of movable parts including a rod and a rack member for transmitting movement of the door to said rod, a compression spring connected at one end to said rod and reacting at the other end against said body portion whereby said spring is compressed as the door is opened and the compressed spring acts to close the door when the door is released, comprising a lost motion connection between said rack member and said rod including a link member pivotally attached at spaced points to said rack member and rod for allowing relative movement between said rack member and rod by rotation of said link member relatively to said pair of parts,

a dog portion on said link member movable to a door holding position through rotation of said link member by relative movement between said pair of movable parts,

a roller on said body portion engageable by said dog portion during a major portion of the movement of said pair of parts in the door opening direction to prevent rotation of said link member and relative movement between said pair of parts,

a relieved portion in said body portion adjacent said roller for releasing said dog portion when said pair of movable parts has moved to a position corresponding to the open position of the door to allow relative movement between said pair of movable parts and resulting rotation of said link member to move said dog portion to door holding position behind said roller to prevent movement of said pair of movable parts in a door closing direction by said compressed closer spring, said link member being rotatable to release said dog portion from behind said roller through relative movement between said pair of movable parts affected by the application of an external force to the door. 

1. A HOLD OPEN MECHANISM FOR A DOOR CLOSER OF THE TYPE HAVING A BODY PORTION, A CLOSER SPRING, AND A PAIR OF PARTS MOVABLE RELATIVELY TO THE BODY PORTION THROUGH WHICH THE CLOSER SPRING IS ENERGIZED AS THE DOOR IS OPENED AND THROUGH WHICH THE ENERGIZED CLOSER SPRING ACTS TO CLOSE THE DOOR WHEN THE DOOR IS RELEASED, COMPRISING, A LOST MOTION CONNECTION BETWEEN SAID PAIR OF MOVABLE PARTS FOR ALLOWING RELATIVE MOVEMENT BETWEEN SAID PARTS, A DOG MEMBER OPERATIVELY CONNECTED TO SAID PAIR OF MOVABLE PARTS AND MOVABLE BY RELATIVE MOVEMENT BETWEEN SAID PARTS, A LIMITING SURFACE ON SAID BODY PORTION ENGAGEABLE BY SAID DOG MEMBER DURING A MAJOR PORTION OF THE MOVEMENT OF SAID PAIR OF MOVABLE PARTS IN THE DOOR OPENING DIRECTION TO PREVENT MOVEMENT OF SAID DOG MEMBER AND RELATIVE MOVEMENT BETWEEN SAID PARTS, A RELIEVED PORTION IN SAID BODY PORTION ADJACENT SAID LIMITING SURFACE FOR RELEASING SAID DOG MEMBER WHEN SAID PAIR OF MOVABLE PARTS HAS MOVED TO A POSITION CORRESPONDING TO THE OPEN POSITION OF THE DOOR TO ALLOW RELATIVE MOVEMENT BETWEEN SAID PAIR OF MOVABLE PARTS AND RESULTING MOVEMENT OF SAID DOG MEMBER TO A DOOR HOLDING POSITION, AND LIMIT MEANS ON SAID BODY PORTION ENGAGED BY SAID DOG MEMBER WHEN SAID DOG MEMBER IS MOVED TO SAID DOOR HOLDING POSITION WHEREBY TO PREVENT MOVEMENT OF SAID PAIR OF MOVABLE PARTS IN A DOOR CLOSING DIRECTION BY SAID CLOSER SPRING, SAID DOG MEMBER BEING MOVABLE TO THE DOOR RELEASING POSITION THROUGH RELATIVE MOVEMENT BETWEEN SAID PARTS AFFECTED BY THE APPLICATION OF FORCE TO THE DOOR. 